Cardiac Protein Kinase D1 ablation alters the myocytes β-adrenergic response.

β-adrenergic (β-AR) signaling is essential for the adaptation of the heart to exercise and stress. Chronic stress leads to the activation of Ca/calmodulin-dependent kinase II (CaMKII) and protein kinase D (PKD). Unlike CaMKII, the effects of PKD on excitation-contraction coupling (ECC) remain unclear.